I think it is really too much to ask of any zoom lens, that it equal that of a good or best prime lens. I do not know if any really do. Too many tradeoffs. I sold off my 24-70L last yr and tried to get along with 14-40 and 70-200L and 50mm macro. Ultimately, although I got some decent results, alway felt that I was missing a mid zoom. After trying a friends 24-70, and still not being satisfied for the money decided that for most of what I shoot with a zoom in this range, my kids, not landscape stuff, non macro, that I would look at non Canon alternatives. Recently bought a Sigma 24-60/2.8 DG. An early opinion, is that it is 90+% of the L mid range for about 1/3 the cost. It is FF and 1/2 the size and fraction of the weitght also. I do not know if it is perfect yet even for my uses, but I feel it is a better tradeoff for its value than the L. So far this is on a 20D, and will see how things are with an eventual 5D.